Roller curtain device

ABSTRACT

The invention relates to a curtain device mounted on a shaft ( 2 ) about which said curtain ( 1 ) can be wound to an open position and unwound into a closed position, a drive wheel ( 7 ) fixed coaxially to said shaft ( 2 ) and cooperating with said curtain ( 1 ) such as to displace the latter between said two positions. The device comprises an oblong flexible control body ( 11 ), cooperating with the drive wheel ( 7 ), said body ( 11 ) being embodied to permit the displacement of the curtain ( 1 ) between the open position and the closed position thereof, independently of the slack formed in the curtain ( 1 ) and to be able to be displaced along at least one of the lateral edges ( 4 ) of the curtain ( 1 ) and act upon the region ( 8 ) of the latter as opposed to that arranged on the shaft ( 2 ).

The invention concerns a curtain device mounted on a shaft around whichthis curtain may be wound toward an open position and from which it canbe unwound toward a closed position, a drive wheel being securedcoaxially on this shaft, preferably on both sides of the curtain, andcooperating with the latter in such a manner so as to move it betweenthese two positions.

The known devices of this type, notably by documents U.S. Pat. No.5,655,591, U.S. Pat. No. 5,392,836, U.S. Pat. No. 5,353,859, U.S. Pat.No. 4,690,194, DE 32 45 009, WO 99/19590 A, GB 1 588 438 A, DE 198 20933 A and EP 1 298 264 A, require that the curtain be taut whiletraveling between its open position and its closed position. Theconsequence of this is that the construction of these devices is verycomplex and very costly owing to the presence of springs, guide pulleys,reduction gears, etc., which generally require very precise adjustmentin order to operate correctly and which are subject to significant wearand frequent repair, especially in cases where the curtain hangs up orbecomes caught.

One of the essential purposes of the present invention is to counterthese drawbacks by presenting a very simple and efficient device whichis economically justified and which enables numerous variants to bedeveloped for various applications. In this manner, it is possible todesign variants enabling a hermetic closure to be obtained, for example,for refrigerators, containers, silos, utility vehicles such as trucks,boats, railcars, and variants in which the curtain extends horizontallyor obliquely in its closed position, etc.

For this purpose, the device according to the invention, comprises anoblong control element that is flexible in terms of its lengthcooperating with the drive wheel, this element being designed in such amanner to allow, on the one hand, the curtain to be moved between itsopen position and its closed position independently of the slack in thecurtain and, on the other hand, to move it along at least one of theside edges of the curtain and act on the zone of the latter oppositethat directed from the side of the aforementioned shaft equallyindependently of possible slack in the curtain.

The control element and its arrangement in the device according to theinvention are thus such to allow slack to form in the curtain when it isbeing moved, without this hampering its operation.

This is not possible with the devices according to prior art in which,on the contrary, all measures are taken to avoid slack. The complexconstruction of these known devices is the result of this requirement.

Advantageously, the pitch diameter of the drive wheel is, on the onehand, less than the diameter of the wound portion of the curtain in itsopen position and, on the other hand, greater than the diameter of theaforementioned shaft or the would portion of the curtain in its closedposition.

Within the scope of the present invention the expression ‘pitchdiameter’ means the distance traveled by the control element from thedrive wheel over a complete a revolution of the latter divided by π.

Other details and features of the present invention will become moreapparent from the following description of a few types of specificembodiments, although not comprehensive, when taken in conjunction withthe accompanying drawings.

FIG. 1 is a diagrammatic front view of a first embodiment of a curtaindevice according to the invention.

FIG. 2 is a diagrammatic view in perspective of a part of the curtaindevice of this first embodiment when the curtain is in the openposition.

FIG. 3 is a view substantially identical to that of FIG. 2 when thecurtain is moving toward its closed position.

FIG. 4 is a view substantially identical to that of FIG. 3 when thecurtain is moving toward its closed position and when the diameter ofthe wound portion of the curtain substantially corresponds to the pitchdiameter of the drive wheel.

FIG. 5 is a view substantially identical to that of FIG. 4 when thecurtain is in its closed position.

FIG. 6 is a cross section, along line VI-VI of FIG. 1, of a guide railin which the control element and the side edge of the curtain areguided.

FIG. 7 is a cross section similar to that of FIG. 6, in which thecontrol element has undergone a 90° twist before entering the guiderail.

FIG. 8 is a side view of a second embodiment of the device according tothe invention in the open position.

FIG. 9 is a side view essentially identical to that of FIG. 8 when thecurtain is moving toward the closed position.

FIG. 10 is a side view essentially identical to that of FIG. 8 when thecurtain is in the closed position.

FIG. 11, drawn to a larger scale, is a detailed representation of thefront of the lower part of the curtain showing one of its side edges ofthis second embodiment.

FIG. 12 is a cross section along line XII-XII in FIG. 11.

FIG. 13 is a cross section along line XIII-XIII in FIG. 9.

FIG. 14 is a diagrammatic view in perspective of part of a curtaindevice according to a third embodiment of the invention.

FIG. 15 is a cross section of a portion of a device according to afourth embodiment of the invention.

FIG. 16 is a diagrammatic view in perspective of a fifth embodiment.

FIG. 17 is a diagrammatic front view of a sixth embodiment.

FIG. 18 is a diagrammatic view in perspective of a seventh embodimentwith the curtain in an intermediary position.

FIG. 19 is a diagrammatic longitudinal cross section along line XIX-XIXin FIG. 18.

FIG. 20 is a view essentially identical to that of FIG. 19 with thecurtain in the closed position.

FIG. 21 concerns a variant of the seventh embodiment and, depicted to alarger scale, is a longitudinal section of part of a guide rail in whicha control element moves.

Generally speaking, the present invention is relative to a windablecurtain device cooperating with drive means allowing the curtain to movebetween an open position and a closed position. It should be noted thatthe curtain can be wound around a shaft which is integral with that ofthe drive means. The curtain is generally intended to close an openingin a wall or any other opening, covering a swimming pool, an area suchas a veranda, or used for creating a screen, for example in front of awindow, etc. Of course, this list is not comprehensive.

Within the scope of the present invention, the term “curtain” refers toall panel or plane surface made of a material that is at least partiallypliant, flexible, semi-rigid, or with one or more stiffeners, such as atarpaulin, a plastic strip, a canvas or metal sheeting, mesh, etc.,which can be wound around a shaft.

It should be noted, however, that marked preference is given to pliantflexible curtains formed, for example, by a tarp, so that thedescription given below shall be limited to a device in which thecurtain is formed by a tarpaulin.

A first embodiment of a curtain device is represented in FIGS. 1 to 6.This device includes a curtain 1, winding and unwinding vertically, thatis secured with its upper edge to a shaft 2 above an opening 3 andextending substantially over the entire Width of the latter. The curtain1 may be moved between an open position, as shown in FIGS. 1 and 2, anda closed position, as shown in FIG. 5. In the open position, the curtain1 is almost entirely wound around the shaft 2 and forms a roll 15, whilein the closed position, the curtain 1 is practically completely unwoundfrom this shaft 2. In certain cases, the curtain 1 can be wound entirelyaround the shaft 2, in such a manner to maintain a maximum amount offree space below the curtain in its open position.

When the curtain 1 moves toward its open or closed position, the sideedges 4 of the curtain 1, which feature an edge roll protruding inrelation to the plane of the curtain, are guided in the guide rails 5mounted on either side of the opening 3 on essentially the entire heightof the latter.

Both sides of the curtain 1 are equipped with a drive wheel 7, formingpart of the aforementioned drive means, which is secured coaxially onsaid shaft 2, such that said shaft 2 and this drive wheel 7 move at thesame angular speed. Each of these drive wheels 7 cooperates with acontrol element 11 enabling the curtain 1 to move toward its closedposition and which, according to the invention, is mounted freely inrelation to the curtain 1, notably in relation to the latter's free edge8 on which it may apply a pushing force.

The drive wheel 7, in particular, consists of a toothed wheel, while thecontrol element 11 is formed by a narrow and flexible oblong strip, butincompressible in terms of its length, such as a strap. This strip isprovided with a series of holes 10 which are evenly spaced along itslongitudinal direction and which mesh with the teeth 9 on the drivewheels 7 at a constant distance in relation to one another around theperiphery of a circle, the center of which is located at the axis 6 ofthe drive wheels 7. In FIGS. 2 to 5, these teeth and holes are notrepresented for clarity purposes.

The diameter d₀ of the drive wheels 7, particularly the pitch diameterof these wheels, is less than the diameter d₁ of the roll 15 when thecurtain 1 is in its open position and greater than the diameter d₂ ofthe shaft 2 or the portion of the curtain 1 still wound in the closedposition. Diameter d₂ is normally slightly greater than the diameter ofthe shaft 2 owing to the fact that, in the closed position, a smallportion of the curtain 1 generally remains wound on the shaft 2.

Preferably, the diameter d₀ is equal to or greater than half the sum ofthe diameters d₁ and d₂.

In the open position, the curtain 1 is practically entirely wound aroundthe shaft 2 and forms successive coils 14, as shown in FIG. 2. In thisposition, each end of the lower edge 8 of the curtain 1, opposite thatmounted on the shaft 2, is held in the guide rails 5.

The control elements 11, the lower end 16 of which is, in the openposition, held in the upper part of the guide rails 5, are also guidedin the respective guide rails 5 when the curtain 1 is opened and closed,as will be described in greater detail in relation with FIG. 6.

In the curtain's 1 open position, as shown in FIG. 2, its lower edge 8is at a distance X below the free end 16 of the corresponding controlelement 11. This distance allows a certain tolerance in the constructionand adjustment of the device according to the invention. The dimensionsof the drive wheel and the control element can be calculated accordingto the curtain's displacement in such a manner to reduce this distanceto zero.

When one wants to move the curtain 1 from its closed position from itsopen position, the shaft 2 is driven by an electric motor 13. As aresult, the roll 15, formed by the coils 14 of the curtain 1, and thedrive wheels 7, which are secured on the shaft 2, are subjected to thesame movement of rotation. The curtain 1, which is held by its sideedges 4 in the guide rails 5, is braked and, in certain cases, evenblocked in its movement toward its closed position by friction whichinevitably exists between its edges 4 and the guide rails 5. Thisresults in that, when starting to close the curtain, the coils 14 of theroll gradually enlarge and detach from one another forming slack, asdiagrammatically represented in FIG. 3. At the same time, the controlelements 11 move in the glide rails 5.

As mentioned above, inasmuch as the movement of the curtain 1 ishindered by said friction between the guide rails 5 and the side edges 4of the curtain 1, the end 16 of the control elements 11 graduallyapproaches the lower edge 8 of the curtain 1. When this lower end 16 isat the height of the lower edge 8 of the curtain, this end 16 rests on apin 17 provided on this lower edge 8, as shown in FIG. 3.

At this time, the control elements 11, driven by the drive wheels 7,exert a pushing force on the lower edge 8 of the curtain 1, such thatthe side edges 4 of the curtain 1 move in the guide rails 5 along theirlongitudinal direction at the same speed as the control element 11.

As soon as the diameter of the roll 15, formed by the wound portion ofthe curtain 1, becomes less than the pitch diameter d₀ of the drivewheel 7, the traveling speed of the control elements 11 becomes greaterthan the circumferential traveling speed of the roll 15. In this manner,the slack formed disappears as the curtain approaches its closedposition, as shown in FIG. 5.

When the curtain 1 is in its closed position, it is nearly completelyunrolled from the shaft 2. However, as already mentioned above, it ispossible that the length of the curtain 1 is greater than the height ofthe opening 3 in order to compensate adjustment tolerances, for example,which may be present, such that, as in this case, a small part of thecurtain may remain wound on the shaft 2.

When the curtain is opened once again, the shaft 2 is actuated by theelectric motor 13 in the direction opposite that which closes thecurtain 1. In this manner, the coils 14 of the curtain 1, which may havepossibly remained on the shaft, are initially taut around the latter andthen the remainder of the curtain 1 is wound normally around the shaft2.

Simultaneously, the control elements 11, which are mounted freely inrelation to the curtain 1, are moved in the guide rails 5 by the actionof the drive wheels 7. Given that the pitch diameter d₀ of these drivewheels 7 is initially greater in diameter than the diameter of the woundportion of the curtain 1, the lower end 16 of the control element 11gradually moves away from the lower edge 8 of the curtain 1. Then, whenthe diameter of the wound portion of the curtain 1 becomes greater thanthe pitch diameter of the drive wheels 7, the contrary occurs, and thecurtain 1 travels at a greater speed in relation to that of the controlelements 11.

When the curtain 1 is in its open position, as shown in FIGS. 1 and 2,the distance between the lower end 16 of the control elements 11 and thelower edge 8 of the curtain 1 is again more or less equal to thedistance X or zero.

The part of the control element 11 that, in its open position, islocated beyond the drive wheels 7 in relation to its lower end 16, maybe collected in an enclosure not shown in the figures.

A cross section of the guide rails 5 is diagrammatically represented inFIG. 6. These guide rails 5 feature two parallel channels 18 and 19 thatextend their entire length.

The first channel 18, featuring a groove 20 directed toward the opening3, houses the side edge 4 of the curtain 1. The portion of the latteradjacent to this side edge 4 extends through the groove 20. In thismanner, the curtain 1 can be moved along the longitudinal direction ofthe guide rails while each of the side edges 4 is guided in said firstchannel 18.

The second channel 19 serves as a guide track for the control element 11along the side edge 4 of the curtain.

In order for the lower end 16 of this control element 11 to be able topress on the pin 17 of the lower edge 8 of the curtain 1, a passageway21 is provided between said channels 18 and 19 extending overessentially the entire length of the latter in order to allow the pin 17to penetrate in the second channel 19 and to cooperate in this mannerwith the control element 11.

The fact that the pin 17 extends though said passageway 21 into thechannel 19 results in that part of this pin is located below the lowerend 16 of the control element 11.

The dimensions of said second channel 19 substantially correspond to thedimensions of the control element 11, such that the latter cannot curveor bend in this channel 19. In this manner, the control element 11,which is essentially incompressible in terms of its longitudinaldirection, can exert a pushing force on the pin 17 provided on the loweredge 8 of the curtain 1 by means of the drive wheel 7 and thus drive thecurtain 1 toward its closed position.

The part of the guide rails 5 defining the channel 19 is,advantageously, extended beyond the level of the axis 6 of the shaft 2,opposite the drive wheel 7 so as to guide the control element 11 as muchas possible. This extension is designated by reference 5′ in thefigures.

The control element 11 consists, for example, of a strip or lance madeof p-phenyleneterephtalamide, known under the brand name “Kevlar”,coated with tetrafluoroethylene, known under the brand name “Teflon”,measuring 2 mm thick and 20 mm wide. This strip has a series of holes 10that cooperate with the teeth 9 on the drive wheel 7, as alreadydescribed above.

In the embodiment, according to the invention, represented in FIGS. 1 to6, the strip, which forms the control element 11, extends in the guiderail 5 substantially in the same plane as the curtain 1, as shown inFIG. 6. The width of the passageway 21, which terminates in the channel19, in which the control element 11 is housed, is thinner than thelatter such that this element cannot enter the passageway 21.

Given that, in the embodiment according to FIGS. 1 to 6, the controlelement 11 is formed by a narrow flexible strip having a rectangularcross section, it is also possible to foresee that the channel 19 ofrectangular cross section extends with its large side in a directionperpendicular in relation to the plane of the curtain 1. In such a case,the control element undergone a 90% twist in the space between the drivewheel 7 and the guide rail 5. In this manner, the width of thepassageway 21 may be greater than the thickness of the control element11, but less than the latter's width, as shown in FIG. 7.

A second embodiment of the curtain device, according to the invention,is represented in FIGS. 8 to 13, which differs in relation to the firstembodiment described above in that the control element is formed by achain 11 meshing with a conventional toothed wheel 7 and that ballasting22 is provided at the lower edge 8 of the curtain 1 opposite the edge ofthe latter which is secured to the shaft 2. The chain 11 is formed by aseries of links articulated between one another around parallel axes,such as a bicycle chain, for example.

The pitch diameter d₀ of the toothed wheel is less than the diameter d₁of the roll 15, which is formed when the curtain 1 is in its openposition, is greater than the diameter d₂ of the portion still wound 15of the curtain 1 when the latter is in the closed position.

When the curtain 1 is being closed, by the rotation of the shaft 2, fromthe open position, as shown in FIG. 8, the curtain 1 unwinds from thisshaft 2 without slack forming owing to the action of the weight providedby the ballasting 22.

The chain 11 also moves in the guide rail 5 as a result of the action ofthe toothed wheel 7. The toothed wheel 7 is secured coaxially on theshaft 2. This chain 11, which does not form a loop, is dispensed from abin 25 installed below the shaft 2.

As mentioned above, when the curtain 1 moves toward its closed position,slack does not normally form around the shaft 2 owing to the tractionaction exerted by the ballasting 22 on the curtain 1.

However, when the side edges 4 of the curtain 1 are braked in the guiderails 5 due to action by the wind, which could exert a pushing force onthe plane of the curtain 1 while the latter is being closed, curtain 1movement stops or is shut down. At this time, slack forms around theshaft 2 and the lower end 16 of the chain 11, which continues to move inthe guide rail 5, approaches the lower edge 8 of the curtain 1 anddrives it. This is, of course, also the case for the first embodimentdescribed above.

Detail of the chain 11 and the pin 17 at the lower edge 8 of the curtain1 is represented in FIG. 11. This pin 17 forms part of an L-shaped part26, the arm of which forms the pin 17 and extends parallel with thelower edge 8 of the curtain 1 in the corresponding guide rail 5, theother arm 27 extending parallel to the corresponding side edge 4 of thecurtain 1. The part 26, in particular, consists of two symmetrical metalplates 28 and 29 which are mounted on either side of the curtain plane1, such that the latter is clamped between these two plates 28 and 29.

The guide rail 5 features a profile such as to guide the chain 11 alongits longitudinal direction without it being able to disengage laterallyin relation to this direction. The side edge 4 of the curtain is held inthe guide rail 5 between the opening 3 and the location where the chain11 is guided, exactly as in the first embodiment.

When a force above a certain value is exerted on the curtain 1transversally to the plane of the latter, for example by a vehiclerunning into the curtain 1, the latter's side edges 4 disengage from theguide rails 5. For this purpose, the side edges 4 of the curtain 1 orthe guide rails 5 can be designed to deform elastically. Given that thechain 11 is not secured to the curtain 1, the pin 17 easily disengagesfrom the chain 11.

FIG. 14 represents a third embodiment of the curtain device, accordingto the invention. it differs essentially from the previous twoembodiments described in that the control element is formed by a loopedbelt 33. This belt 33 is guided and driven by the drive wheels 7 mountedon the shaft 2. These drive wheels can, in this case, be replaced bypulleys.

In the lower part of the opening 3, this belt 33 cooperates with aroller 34, which is preferably resiliently mounted in relation to thefloor by means of coil springs 40 for example, in order to maintain itconstantly taut.

A contact element 35, formed by a boss or hook for example, is mountedon the belt 33 between this lower edge 8 and the shaft 2.

When the curtain 1 moves under the rotation of the shaft 2, thesuccessive coils 14 of the roll 15 become larger and form slack as inthe first embodiment. Simultaneously, the belt 33 is moved following theaction of the drive wheel 7 and the contact element 35 approaches thelower edge 8. When the contact element 35 touches the pin 17 of thelower edge 8, it exerts a force on this lower edge 8 in order to movethe curtain 1 toward its closed position. As this contact element 35moves, the coils of the curtain 1 unwind and the slack diminishes. Infact, this contact element 35 fulfils the same role as the controlelement's free end 16 of the first and second embodiment.

When the curtain is reopened from its closed position, the shaft 2 turnsin the direction opposite that of closure, such that the curtain iswound without slack onto the shaft 2. Given that the diameter of thedrive wheel 7 is, at this time, greater than the wound portion of thecurtain 1, the contact element 35 moves away from the lower edge 8 ofthe curtain until these diameters are substantially equal. While theremaining portion of the curtain 1 is being wound, its lower edge 8gradually comes to within a short distance from the contact element 35,at the moment when the curtain is in the open position.

FIG. 15 concerns a fourth embodiment which is characterized in relationto the previous embodiments described in that the curtain 1 is woundaround a drum 36 which is coaxial with the shaft 2 and which is mountedfreely on the latter. The side face of this drum 36, directed toward thedrive wheel 7, is equipped with a stop 37 which cooperates with a stop38 located on the drive wheel 7 side opposite the drum 36. Both stops 37and 38 are mounted at the same distance from the axis 6 of the shaft 2.

Initially, when the shaft 2 and the drive wheel 7 begin to rotate inorder to move the curtain 1 toward its closed position, the controlelements, not represented in FIG. 15, move toward the edge of thecurtain 1 opposite that mounted on the drum 36 while the latter remainsmore or less immobile. At the moment when these elements act on thisedge, the curtain 1 unwinds at the same linear speed as the controlelement. The consequence of this is that the drum 36 rotates at anangular speed less than that of the drive wheel 7 given that thediameter of the wound portion of the curtain is greater than thediameter of the drive wheel 7.

As soon as the diameter of the wound portion of the curtain 1 has becomemore or less equal to the diameter of the drive wheel 7, the drum turnsat the same angular speed as the drive wheel. As the diameter of thewound portion of the curtain 1 decreases in relation to the diameter ofthe drive wheel 7, the rotation speed of the drum 36 increases inrelation to that of the drive wheel 7 up to the curtain's closedposition. The device can be dimensioned so that the stop 37 comes intocontact with the stop 38 when the curtain reaches its closed position.It is, however, possible to plan that even in the closed position, thesestops 37 and 38 do not touch.

In this embodiment, the device's dimensions are selected such that noslack forms in the curtain 1 while it is being closed. During thisclosing operation, the drum 36 only turns around its axis 6 by theaction of the lower end of the control elements 11 on the pins providedfor this purpose at the edge of the curtain 1 opposite the one on theshaft 2 side. There is no contact between stops 37 and 38 while thecurtain 1 is moving toward the closed position.

When the curtain 1 opens from its closed position by the rotation of theshaft 2 in the opposite direction in relation to that during closure,the stop 38 of the drive wheel 7 presses against the stop 37 of the drum36 such that the latter is actuated by the drive wheel 7 and that thecurtain 1 is wound around the drum 36. Given that when the curtain 1begins to open, the diameter of the wound portion of the curtain 1 isless than the diameter of drive wheel 7, the control element 11 israised faster than the curtain 1.

It is clear that when the opening to be closed by the curtain is veryhigh, slack may form when the curtain is closed when the stops 37 and 38touch during the closing operation. In this case, this slack is lesssignificant in relation to the other embodiments described above.

The drum assembly 36 and stops 37 and 38 form a compensator designed toreduce or avoid the formation of slack during curtain travel. Theconstruction of this compensator is very simple and does not requiresprings, for example.

In an embodiment of the curtain device where a compensator is provided,it is also possible to secure the lower end of the control element, orthe contact element 35, to the pin 17 in a removable manner. In thismanner, the edge of the curtain 1 opposite the one oriented toward shaft2 is connected to the control elements throughout the entire closing andopening cycle and until the side edges 4 of the curtain 1 disengage fromthe guide rails, for example, by a vehicle running into the curtain 1.In such a case, the lower end 16 of the control element, or the contactelement 35, is automatically separated from the pin 17.

In addition, the free end 16 of the lance which is to cooperate with thecurtain is preferably beveled as is the pin 17, in such a manner as tofacilitate the disengagement of the side edge 5 of the curtain 1 fromthe guide rails due to an encounter with an obstacle, as indicatedabove.

In the second embodiment, a beveled end-piece can be placed at the freeend of the chain 11, in the same manner as the end of the lance.

FIG. 16 is relative to a fifth embodiment which is characterized inrelation to the first embodiment represented in FIG. 2, by the fact thatthe end of the strip 11, which forms the control element, is secured byits opposite end to that is acting on the curtain 1 on the shaft 2 andthat this strip 11 is wound or unwound between the coils 14 of the roll15 of the curtain 1. This avoids having to use a bin, as in the secondembodiment, to house the part of the control element, formed by a strapor a lance, beyond the drive wheel.

In order to be able to compensate the difference in diameter between thewound portion of the curtain 1 and the drive wheel 7, the strip 11 isprovided sufficient length to allow the outer coil 12 of the woundportion of this strip 11 to be able to form a loop in the same manner asslack around the shaft 2.

FIG. 17 concerns an embodiment that differs from the previousembodiments described in that the control element formed by anincompressible strap 11, is wound in a spiral manner on a truncatedconical drive wheel 7, toothed or otherwise, the form of which is suchthat, during either unwinding or winding, the linear travel speed of thestrap corresponds to that of the curtain 1 between its open position andclosed position.

When this wheel 7 is not toothed, grooves, not represented, arepreferably provided in the outer surface of the wheel, which extendspirally around the axis 6 and in which the control element moves 11. Ahousing 47 is provided around the drive wheel 7 which features a slot 48in its lower part, which extends in the plane passing through the axis 6of the shaft 2 and parallel to the direction of travel of the curtain 1between its open position and its closed position through which thecontrol element 11 can be wound onto or unwound from the drive wheel 7.

In other cases, for example for covering swimming pools, verandas, etc.,if, on the contrary, to prevent the side edges of the curtain fromexiting the guide rails, the rails are made of a rigid material orrendered rigid. Furthermore, the pins are secured to the edge of thecurtain opposite that of the side of the shaft on which the curtain ismounted and are held in a sliding manner in the guide rails. This isthus possible only for embodiments where the control element isconstantly in contact with the pin during curtain travel.

FIGS. 18 to 20 show an embodiment in which the curtain travelshorizontally between an open position and a closed position. The edge 8of the curtain 1 opposite that of the shaft 2 side is formed by a rigidbar, the ends of which form the pins which slide in the guide rails 5,such that the pins cannot disengage from the latter.

In order to tighten the curtain 1 in its closed position, addedthickness 41, preferably rigid, extends along the entire width of theoutside face of the curtain 1, parallel to the axis of the shaft 2 andrests against a rigid crossbar 42 also extending parallel to the axis ofthe shaft 2 when the curtain is in the closed position. This crossbar 42is mounted on the fixed part of the device, such as the guide rails 5.

The distance traveled by the curtain from the crossbar 42 to its closedposition must thus correspond to the distance between the addedthickness 41 and the edge 8 of the curtain 1. In this respect, theposition of the crossbar 42 as well as the added thickness 41 may beadjusted.

This allows any slack that may be present to remain in the part of thecurtain 1 upstream from this added thickness 41. This solution isespecially important for devices which do not have guide rails for theside edges of the curtain 1 or for which it is not possible to provideballasting of the lower edge of the curtain opposite that of the shaft 2side. This is the case, for example, when the curtain travelshorizontally and whose side edges are not guided, as shown in FIGS. 18to 20.

FIG. 21 concerns a feature that may be adapted on practically allembodiments described above, but which is especially useful forrelatively long curtains and/or which travel with relatively significantfriction in guide rails. This may be the case in the embodiment shown inFIGS. 18 to 20.

This feature consists in providing an opening 43 in the guide rails 5,near the drive wheel for example, between the open position and closedposition of the curtain, in which the control element 11 can penetrateduring its movement in the guide rail 5 at the moment when anobstruction occurs in the guide rail beyond this opening 43 consideringthe direction of travel of the control element 11.

In such a case, the part 11′ of the control element 11 passing throughthis opening 43 actuates a detector 44 which sends a signal to a controlstation, not shown. This control station may possibly actuate amechanism to correct the problem.

In the previous embodiments, the control element and the side edges ofthe curtain travel in the same guide rail. It is, however, possible toprovide a guide rail, or other separate means, to guide the controlelement that is entirely independent of the guide rails for the sideedges of the curtain and which allows, for example, the control elementto move in a rectilinear path to or from the drive wheel.

In the curtain devices according to the invention, described above, adrive wheel 7, which is secured to the shaft 2, is provided on each sideof the curtain. In this manner, the movement of the correspondingcontrol elements is entirely synchronized.

Preferably, the curtain 1 is made of a material that allows thesuccessive coils of the wound curtain to slide on one another, such thatthe curtain is, for example, made of a smooth and continuous material,such as a tarp or possibly polished plastic material for example.

When the control element is formed by a lance or an incompressible strapwhich is not looped, as in the embodiments described above, except forthe third embodiment, this control element interacts with the curtainonly to move it toward its closed position, the opening being performedby the rotation of the shaft 2 around its axis 6 in the directionopposite that used for closing.

It is also recommended to select the length of the curtain slightlylonger than the height of the opening such that a slight amount of slackis present around the shaft 2 equally in the closed position. Thisallows for compensation of variations in the dimensions of the deviceand the opening, as well as to account for temperature variations thatmay have an effect on the length of the curtain.

Finally, in certain cases, the pin provided at the edge of the curtainopposite that of the shaft side may be removable, by means of a leverfor example, to allow for easier installation and assembly of the deviceand also to facilitate the reintroduction of this pin into the guiderails following a disengagement of the contract from the latter,especially when the edge of the curtain opposite that of the shaft 2side features a rigid bar, as in the seventh embodiment.

Although the curtain devices described above are equipped with guiderails, it is clear that the presence of these guide rails is notessential for the invention.

Of course, the invention is not limited to the various embodimentsdescribed above, and other variants may be considered without deviatingfrom the scope of the invention.

For devices of reduced size, the curtain and the drive wheels may beactuated manually, for example, by means of a lever mounted on thecurtain's wrapping drive.

In certain cases, if the curtain is made of a sufficiently heavymaterial, ballasting may be omitted.

In the seventh embodiment, the rigid bar of the edge 8 may be replacedby two studs at each of the ends of this edge which engage in the guiderails.

Furthermore, in each of the embodiments described above, means areadvantageously provided enabling a maximum of one coil of the controlelement around the drive wheel parallel to the plane perpendicular tothe axis of the shaft 2, such that the pitch diameter of the drive wheelremains more or less constant. In this manner, the control element willalways travel at the same speed during curtain closing and openingoperations. The aforementioned means are those that prevent the controlelement from winding onto itself around the drive wheel.

1. A curtain device mounted on a shaft (2) around which the curtain (1)may be wound toward an open position and from which it can be unwoundtoward a closed position, a drive wheel (7) secured coaxially on theshaft (2) and cooperating with the curtain (1) in such a manner so as tomove the latter between these two positions, wherein the devicecomprises a flexible oblong control element (11) that cooperates withthe drive wheel (7), said control element (11) being mounted freely inrelation to the curtain in such a manner to allow the curtain (1) to bemoved between an open position and a closed position independently ofslack which may form in the curtain (1), on the one hand, and to be ableto move along at least one of the side edges (4) of the curtain (1) andact on the zone (8) of the latter opposite that mounted on the shaft(2), on the other hand, wherein the pitch diameter of the drive wheel(7) is less than the diameter of the wound portion of the curtain (1) inits open position, and is greater than the diameter of theaforementioned shaft (2) or the wound portion of the curtain (1) in itsclosed position.
 2. The device according to claim 1, wherein the pitchdiameter of the drive wheel (7) is greater than or equal to half the sumof the diameter of the wound portion of the curtain (1) in its openposition, and of the diameter of the aforementioned shaft (2) or thewound portion of the curtain (1) in its closed position.
 3. The deviceaccording to claim 1, further comprising means provided to enable amaximum of one coil of the control element (11) to be wound around thedrive wheel (7) parallel to a plane perpendicular to the axis (6) of theshaft (2).
 4. The device according to claim 1, wherein the controlelement (11) is incompressible in terms of its length.
 5. The deviceaccording to claim 1, wherein the control element (11) is such that itcan exert a pushing force on the curtain (1) to bring it to its closedposition.
 6. The device according to claim 1, wherein the controlelement (11) comprises an incompressible element in terms of its length.7. The device according to claim 1, wherein the drive wheel (7) featuresa series of bosses or indentations (9) cooperating with the controlelement (11) and evenly spaced in relation to one another along theperiphery of a circle, the center of which is located on the axis (6) ofthe foresaid wheel (7).
 8. The device according to claim 7, wherein thecontrol element (11) includes an endless tape or chain.
 9. The deviceaccording to claim 1, further comprising means are provided for thecurtain (1) to avoid slack from forming in the latter when it is beingunwound.
 10. The device according to claim 9, wherein said means toavoid slack include ballasting (22) at the edge of the curtain (1)opposite to that mounted on the aforesaid shaft (2).
 11. The deviceaccording to claim 1, wherein the drive wheel is secured coaxially onthe shaft (2) in such a manner to be able to travel at the same angularspeed as this shaft (2).
 12. The device according to claim 1, furthercomprising guide rails (5) in which the side edges (4) of the curtain(1) and the control element (11) can travel parallel to one another. 13.A curtain device mounted on a shaft (2) around which the curtain (1) maybe wound toward an open position and from which it can be unwound towarda closed position, a drive wheel (7) secured coaxially on the shaft (2)and cooperating with the curtain (1) in such a manner so as to move thelatter between these two positions, wherein the device comprises aflexible oblong control element (11) that cooperates with the drivewheel (7), said control element (11) being mounted freely in relation tothe curtain in such a manner to allow the curtain (1) to be movedbetween its open position and its closed position independently of theslack which may form in the curtain (1), on the one hand, and to be ableto move along at least one of the side edges (4) of the curtain (1) andact on the zone (8) of the latter opposite that mounted on the shaft(2), on the other hand, wherein the drive wheel (7) is such that thecontrol element (11) can be wound spirally on it around its axis ofrotation.
 14. The device according to claim 13, wherein the drive wheel(7) has a truncated conical form such that, during both unwinding andwinding of the control element, the linear speed of the latteressentially corresponds to that of the curtain (1) traveling between itsopen position and its closed position.
 15. The device according to claim1, further comprising a compensator is mounted on the aforementionedshaft (2) enabling the wound portion of the curtain (1) to be adapted tothe travel of the control element (11).